Cellular communication devices use various network radio access technologies to communicate wirelessly with geographically distributed base stations. Long-Term Evolution (LTE) is an example of a widely implemented radio access technology used in 4th-Generation (4G) communication systems. New Radio (NR) is a newer radio access technology that is used in 5th-Generation (5G) communication systems. Standards for LTE and NR radio access technologies have been developed by the 3rd Generation Partnership Project (3GPP) for use by wireless communication carriers within cellular communication networks.
A communication protocol defined by the 3GPP, referred to as Non-Standalone (NSA), specifies the simultaneous use of LTE and NR for communications between a mobile device and a communication network. Specifically, NSA uses Dual Connectivity (DC), in which a user equipment (UE) uses both LTE and NR carriers for uplink communications with corresponding 4G and 5G base stations. LTE carriers are used for control-plane messaging and for user-plane communications. NR carrier are used for additional user-plane bandwidth.